1. Field of the Invention
This invention relates to a means for printing on printing on both sides of a paper document, and, more particularly, to printing automatically on both sides of a check at a point of sale terminal with a single print mechanism.
2. Description of the Related Art
In continuing attempts to provide more efficient and convenient service to customers, many retailers have begun to use "point of sale check printers" to reduce the time required for a customer to fill out and sign a check. Such a printer automatically enters the date, amount of purchase, and the name of the retail establishment, to which payment is being made, in the corresponding spaces of a check provided by the customer. The signature line is left blank, for the customer to sign after he has been presented with the printed check.
Another form of printing performed on a check by the retailer is the printing of franking information on the reverse side of the check. This information generally indicates that the check is for deposit only or that it is to be deposited only to a particular account. While it is not necessary to perform this printing operation at the point of sale, many retail establishments have a policy of printing this information, with a rubber stamp if necessary, at the point of sale, reducing the possibility of unrecoverable losses from checks stolen without franking information, which are later stamped or printed with forged information. It is therefore desirable for a point of sale check printer to be able to print on both sides of the check, with the amount of the check and the name of the retail establishment being printed on the front side of the check, and with the franking information being printed on the reverse side.
One method for printing on both sides of a check simply places an additional burden on the cashier using the point of sale terminal. The check is inserted into the printer for printing on a first side, removed, turned over, and then inserted into the printer for printing on the second side. While this method is the simplest in terms of the hardware required, the additional operations required to be performed by the cashier increase the time required for a transaction while also reducing the chance that the printing operation will be performed correctly.
Some printers provide for printing on both sides of a sheet of paper with two separate print mechanisms, operating on opposite sides of the sheet of paper. However, this approach naturally increases the complexity of the printer mechanism while tending to reduce its reliability.
The patent art describes other printers which provide for printing on both sides of the paper with a single print head. U.S. Pat. No. 4,755,071 describes a device in which printing is performed on both sides of a sheet of paper fed between a wire matrix print head and a cylindrical platen extending parallel to the direction in which the print head is reciprocated. The cylinder has a solid segment and a porous segment, composed, for example, of a sintered Nylon, impregnated with ink. Printing on a front side of the paper occurs as the print head is moved in an advancing direction, with an ink-impregnated printing ribbon extending between the print head and the paper, and with the platen rotated so that the solid segment is adjacent the paper in the area where printing is taking place. Printing on the back side of the paper occurs as the print head is returned opposite the advancing direction, with the ribbon lifted out of engagement with the print head wires, and with the platen rotated so that a porous, inked segment extends adjacent the paper in the area where printing is taking place. Multicolor printing can be accomplished with multicolored strips of ink extending along the ribbon and with multiple segments of the platen having different colors of ink.
Japanese Application, Publication Number 01-186369, published Jul. 25, 1989, describes another method for printing on both sides of the paper with a single print head, with the paper being fed between a pair of printing ribbons. Each of the printing ribbons includes a strip infiltrated with ink and a strip without ink. The ribbons are arranged so that the inked portion of each ribbon is adjacent the non-inked portion of the other ribbon. For example, a first side of the document is printed with the print head moving in an advancing direction, and with both ribbons in a raised position, so that the inked portion of the first ribbon lies adjacent the print head and the non-inked portion of the second ribbon. The second side of the document is printed as the head is returning opposite the advancing direction, and with both ribbons in a lowered position, so that the inked portion of the second ribbon lies adjacent the print head and the non-inked portion of the first ribbon.
Because of the nature of information to be printed on a check, and because of long-standing conventions in the banking industry, it is particularly desirable to provide biaxial printing at a point of sale check printing terminal. The information to be printed on the front side of the check, such as the organization to which payment is to be made and the amount to be paid, must be printed in a longitudinal direction along the check, while the franking information to be printed on the reverse side of the check must be printed in a transverse direction along a relatively narrow area at an end of the check. Printing in the longitudinal direction, parallel to a long side of a document, is generally called "landscape" printing, while printing in the transverse direction, parallel to a short side of the document, is generally called "portrait" printing.
Thus, the inventions of U.S. Pat. No. 4,755,071 and Japanese Application, Publication No. 01-186369 have a disadvantage, when considered for use in a point of sale check printer, of printing a line at a time on alternating sides of the document. There is no provision for printing in directions perpendicular to one another.
U.S. Pat. No. 5,533,817 describes a biaxial printer having a print head with a column of print wires arranged at an angle between 0 and 90 degrees relative to a permitted line of motion of the print head. For example, the column may be arranged at 45 degrees relative to this line of motion. This angled print head allows for both portrait and landscape printing, with portrait mode printing being performed by controlling movement of the angled print head along the permitted line of motion during the printing of each line of images, and with landscape mode printing being performed by maintaining a stationary position of the print head while the document is moved in a direction perpendicular to the permitted line of motion of the print head. This type of printing is particularly useful for the application of point-of-sale check printing, since only two or three lines of information is to be printed on each side of the check. In such an application, it is particularly desirable to be able to finish the printing operation quickly, since there often are a number of people waiting in line to check out merchandise.
U.S. Pat. No. 5,865,547 describes a print head and check flipper subassembly having a removable flipper cartridge to allow printing on both sides of a check or other document in one continuous operation. A check is fed downward, between a print head and platen, with printing occurring on a first side of the check, and into a loop within the flipper cartridge. The check continues around the loop, and is driven out of the loop, having been reversed front to back. The check is fed upward between the print head and platen, with printing occurring on a second side of the check, and outward through the slot into which it has been inserted. This patent also describes the use of a Magnetic Ink Character Recognition (MICR) reader to read the characters extending along the lower edge of the check to determine the customers bank and his account number.
What is needed is a printer capable of printing on both sides of a document, and in directions perpendicular to one another, without requiring the complexity of a paper path having a capability of flipping the document.